Edgy/Scarff,

If I remember correctly, here are some of the conditions for after-hours trades:

1. Can only occur on Toronto, not on the Venture or other exchanges.

2. Can only occur for 59 minutes after the close of regular trading.

3. Can only occur at the same price as the closing price.

So in other words, if the last trade was a buy for some stock at $4.29, then someone could, for 59 minutes after the close of regular trading, buy any amount at $4.29 up to the amount offered on the sell side at that price.

If the last trade was a sell at $6.22, then others could, for 59 minutes, sell to the market for $6.22 each until the amount of bids at $6.22 was exhausted.

I don't believe that new orders placed after 4pm are considered. This means that news released a minute after market close can be acted upon, technically, by a very small number of traders. But that amount is insignificant. So for example, if the last trade in a stock is for $9.55, then a whole bunch of bids and sells at $9.55 can't both be executed for 59 minutes. Only the pre-existing bids or sells on the side which established the price.

I'm not 100% sure I'm correct on the details above ... I don't really pay attention to this. But I do vaguely remember when this rule came into effect. It must be at least a decade ago, if I had to guess. And I don't believe the smaller exchanges have adopted it. I think this all started back when the exchanges were Toronto/Vancouver/Montreal, which wasn't really that long ago.

Also, I think online broker trades can participate, but I'm not too certain on that. There's a possibility that this is restricted to institutions and/or trades placed directly through certain brokers. Again, I'm not positive, my memory of this situation is vague.